A mountain lion with a rare physical abnormality has wildlife officials in Southeast Idaho stumped.

The yearling cougar, which was harvested near Weston last week by an unidentified hunter, had a separate set of teeth growing out the side of its forehead. The community of Weston is located about 12 miles southwest of Preston near the Idaho/Utah border.

After the conservation officer who inspected the animal sent in photos of the lion’s deformity to Idaho Fish and Game’s Southeast Regional Office in Pocatello, wildlife biologists were stunned by what they saw.

“It has all of us scratching our heads,” said regional wildlife biologist Zach Lockyer. “It’s a bizarre situation and a bizarre photo.”

Lockyer said the teeth were growing out of hard tissue on the left side of the animal’s forehead, an abnormality local Fish and Game biologists say they have never seen before.

What would cause this type of deformity?

Fish and Game biologists and veterinarians have a few theories.

For one, the teeth could be the remnants of a conjoined twin that died in the womb and was absorbed into the lion killed last week. Conjoined animals in nature are very rare occurrences.

The biologists and veterinarians said it could also be a teratoma, which is a rare tumor that can contain hair, teeth and bones. In rare circumstances, a teratoma can also sprout more complex body parts such as eyes, fingers or toes.

Like conjoined twins, teratomas are rare in both humans and animals but have been documented in canines and horses.

A third theory, which Lockyer believes is unlikely, is that the mountain lion suffered an injury to its jaw and the teeth healed in an unusual way, causing the abnormality. However, the pictures do not show any evidence of an injury to the mouth, and it appears the lion possesses a normal set of chompers in its mouth.

According to biologists, the hunter who bagged the cougar plans to take the carcass to a taxidermist. But Fish and Game said it plans to reach out to the hunter to bring the lion in for an in-depth analysis.

If wildlife biologists cannot perform X-rays and a detailed analysis of the mountain lion’s head to confirm or disprove their theories, the mystery of the deformity could remain just that — a mystery.

“We may never know why those teeth are there,” Lockyer said.

For more local wildlife news, visit XtremeIdaho.com, the Idaho State Journal’s outdoors website.